X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fchan_utils.rs;h=408f1cd7e477ca3eb0e4acde601cde9eb0c908f1;hb=5e14c24a11f610ab8c402f788ec5bd637e9e24af;hp=d53863289bc5807464739f0707fbb390c25f9869;hpb=12687d75d5a0eba4bc691998e51a5313c715e559;p=rust-lightning diff --git a/lightning/src/ln/chan_utils.rs b/lightning/src/ln/chan_utils.rs index d5386328..408f1cd7 100644 --- a/lightning/src/ln/chan_utils.rs +++ b/lightning/src/ln/chan_utils.rs @@ -14,34 +14,47 @@ use bitcoin::blockdata::script::{Script,Builder}; use bitcoin::blockdata::opcodes; use bitcoin::blockdata::transaction::{TxIn,TxOut,OutPoint,Transaction, EcdsaSighashType}; use bitcoin::util::sighash; +use bitcoin::util::address::Payload; use bitcoin::hashes::{Hash, HashEngine}; use bitcoin::hashes::sha256::Hash as Sha256; use bitcoin::hashes::ripemd160::Hash as Ripemd160; use bitcoin::hash_types::{Txid, PubkeyHash}; -use ln::{PaymentHash, PaymentPreimage}; -use ln::msgs::DecodeError; -use util::ser::{Readable, Writeable, Writer}; -use util::{byte_utils, transaction_utils}; +use crate::ln::{PaymentHash, PaymentPreimage}; +use crate::ln::msgs::DecodeError; +use crate::util::ser::{Readable, Writeable, Writer}; +use crate::util::transaction_utils; -use bitcoin::hash_types::WPubkeyHash; use bitcoin::secp256k1::{SecretKey, PublicKey, Scalar}; use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature, Message}; -use bitcoin::secp256k1::Error as SecpError; use bitcoin::{PackedLockTime, secp256k1, Sequence, Witness}; +use bitcoin::PublicKey as BitcoinPublicKey; -use io; -use prelude::*; +use crate::io; +use crate::prelude::*; use core::cmp; -use ln::chan_utils; -use util::transaction_utils::sort_outputs; -use ln::channel::{INITIAL_COMMITMENT_NUMBER, ANCHOR_OUTPUT_VALUE_SATOSHI}; +use crate::ln::chan_utils; +use crate::util::transaction_utils::sort_outputs; +use crate::ln::channel::{INITIAL_COMMITMENT_NUMBER, ANCHOR_OUTPUT_VALUE_SATOSHI}; use core::ops::Deref; -use chain; -use util::crypto::sign; - -pub(crate) const MAX_HTLCS: u16 = 483; +use crate::chain; +use crate::util::crypto::sign; + +/// Maximum number of one-way in-flight HTLC (protocol-level value). +pub const MAX_HTLCS: u16 = 483; +/// The weight of a BIP141 witnessScript for a BOLT3's "offered HTLC output" on a commitment transaction, non-anchor variant. +pub const OFFERED_HTLC_SCRIPT_WEIGHT: usize = 133; +/// The weight of a BIP141 witnessScript for a BOLT3's "offered HTLC output" on a commitment transaction, anchor variant. +pub const OFFERED_HTLC_SCRIPT_WEIGHT_ANCHORS: usize = 136; + +/// The weight of a BIP141 witnessScript for a BOLT3's "received HTLC output" can vary in function of its CLTV argument value. +/// We define a range that encompasses both its non-anchors and anchors variants. +pub(crate) const MIN_ACCEPTED_HTLC_SCRIPT_WEIGHT: usize = 136; +/// The weight of a BIP141 witnessScript for a BOLT3's "received HTLC output" can vary in function of its CLTV argument value. +/// We define a range that encompasses both its non-anchors and anchors variants. +/// This is the maximum post-anchor value. +pub const MAX_ACCEPTED_HTLC_SCRIPT_WEIGHT: usize = 143; /// Gets the weight for an HTLC-Success transaction. #[inline] @@ -59,19 +72,79 @@ pub fn htlc_timeout_tx_weight(opt_anchors: bool) -> u64 { if opt_anchors { HTLC_TIMEOUT_ANCHOR_TX_WEIGHT } else { HTLC_TIMEOUT_TX_WEIGHT } } -#[derive(PartialEq)] -pub(crate) enum HTLCType { - AcceptedHTLC, - OfferedHTLC +/// Describes the type of HTLC claim as determined by analyzing the witness. +#[derive(PartialEq, Eq)] +pub enum HTLCClaim { + /// Claims an offered output on a commitment transaction through the timeout path. + OfferedTimeout, + /// Claims an offered output on a commitment transaction through the success path. + OfferedPreimage, + /// Claims an accepted output on a commitment transaction through the timeout path. + AcceptedTimeout, + /// Claims an accepted output on a commitment transaction through the success path. + AcceptedPreimage, + /// Claims an offered/accepted output on a commitment transaction through the revocation path. + Revocation, } -impl HTLCType { - /// Check if a given tx witnessScript len matchs one of a pre-signed HTLC - pub(crate) fn scriptlen_to_htlctype(witness_script_len: usize) -> Option { - if witness_script_len == 133 { - Some(HTLCType::OfferedHTLC) - } else if witness_script_len >= 136 && witness_script_len <= 139 { - Some(HTLCType::AcceptedHTLC) +impl HTLCClaim { + /// Check if a given input witness attempts to claim a HTLC. + pub fn from_witness(witness: &Witness) -> Option { + debug_assert_eq!(OFFERED_HTLC_SCRIPT_WEIGHT_ANCHORS, MIN_ACCEPTED_HTLC_SCRIPT_WEIGHT); + if witness.len() < 2 { + return None; + } + let witness_script = witness.last().unwrap(); + let second_to_last = witness.second_to_last().unwrap(); + if witness_script.len() == OFFERED_HTLC_SCRIPT_WEIGHT { + if witness.len() == 3 && second_to_last.len() == 33 { + // + Some(Self::Revocation) + } else if witness.len() == 3 && second_to_last.len() == 32 { + // + Some(Self::OfferedPreimage) + } else if witness.len() == 5 && second_to_last.len() == 0 { + // 0 <> + Some(Self::OfferedTimeout) + } else { + None + } + } else if witness_script.len() == OFFERED_HTLC_SCRIPT_WEIGHT_ANCHORS { + // It's possible for the weight of `offered_htlc_script` and `accepted_htlc_script` to + // match so we check for both here. + if witness.len() == 3 && second_to_last.len() == 33 { + // + Some(Self::Revocation) + } else if witness.len() == 3 && second_to_last.len() == 32 { + // + Some(Self::OfferedPreimage) + } else if witness.len() == 5 && second_to_last.len() == 0 { + // 0 <> + Some(Self::OfferedTimeout) + } else if witness.len() == 3 && second_to_last.len() == 0 { + // <> + Some(Self::AcceptedTimeout) + } else if witness.len() == 5 && second_to_last.len() == 32 { + // 0 + Some(Self::AcceptedPreimage) + } else { + None + } + } else if witness_script.len() > MIN_ACCEPTED_HTLC_SCRIPT_WEIGHT && + witness_script.len() <= MAX_ACCEPTED_HTLC_SCRIPT_WEIGHT { + // Handle remaining range of ACCEPTED_HTLC_SCRIPT_WEIGHT. + if witness.len() == 3 && second_to_last.len() == 33 { + // + Some(Self::Revocation) + } else if witness.len() == 3 && second_to_last.len() == 0 { + // <> + Some(Self::AcceptedTimeout) + } else if witness.len() == 5 && second_to_last.len() == 32 { + // 0 + Some(Self::AcceptedPreimage) + } else { + None + } } else { None } @@ -148,6 +221,7 @@ pub struct CounterpartyCommitmentSecrets { old_secrets: [([u8; 32], u64); 49], } +impl Eq for CounterpartyCommitmentSecrets {} impl PartialEq for CounterpartyCommitmentSecrets { fn eq(&self, other: &Self) -> bool { for (&(ref secret, ref idx), &(ref o_secret, ref o_idx)) in self.old_secrets.iter().zip(other.old_secrets.iter()) { @@ -235,7 +309,7 @@ impl Writeable for CounterpartyCommitmentSecrets { fn write(&self, writer: &mut W) -> Result<(), io::Error> { for &(ref secret, ref idx) in self.old_secrets.iter() { writer.write_all(secret)?; - writer.write_all(&byte_utils::be64_to_array(*idx))?; + writer.write_all(&idx.to_be_bytes())?; } write_tlv_fields!(writer, {}); Ok(()) @@ -255,44 +329,40 @@ impl Readable for CounterpartyCommitmentSecrets { /// Derives a per-commitment-transaction private key (eg an htlc key or delayed_payment key) /// from the base secret and the per_commitment_point. -/// -/// Note that this is infallible iff we trust that at least one of the two input keys are randomly -/// generated (ie our own). -pub fn derive_private_key(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> Result { +pub fn derive_private_key(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> SecretKey { let mut sha = Sha256::engine(); sha.input(&per_commitment_point.serialize()); sha.input(&PublicKey::from_secret_key(&secp_ctx, &base_secret).serialize()); let res = Sha256::from_engine(sha).into_inner(); base_secret.clone().add_tweak(&Scalar::from_be_bytes(res).unwrap()) + .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak contains the hash of the key.") } /// Derives a per-commitment-transaction public key (eg an htlc key or a delayed_payment key) /// from the base point and the per_commitment_key. This is the public equivalent of /// derive_private_key - using only public keys to derive a public key instead of private keys. -/// -/// Note that this is infallible iff we trust that at least one of the two input keys are randomly -/// generated (ie our own). -pub fn derive_public_key(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, base_point: &PublicKey) -> Result { +pub fn derive_public_key(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, base_point: &PublicKey) -> PublicKey { let mut sha = Sha256::engine(); sha.input(&per_commitment_point.serialize()); sha.input(&base_point.serialize()); let res = Sha256::from_engine(sha).into_inner(); - let hashkey = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&res)?); + let hashkey = PublicKey::from_secret_key(&secp_ctx, + &SecretKey::from_slice(&res).expect("Hashes should always be valid keys unless SHA-256 is broken")); base_point.combine(&hashkey) + .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak contains the hash of the key.") } /// Derives a per-commitment-transaction revocation key from its constituent parts. /// -/// Only the cheating participant owns a valid witness to propagate a revoked +/// Only the cheating participant owns a valid witness to propagate a revoked /// commitment transaction, thus per_commitment_secret always come from cheater /// and revocation_base_secret always come from punisher, which is the broadcaster /// of the transaction spending with this key knowledge. -/// -/// Note that this is infallible iff we trust that at least one of the two input keys are randomly -/// generated (ie our own). -pub fn derive_private_revocation_key(secp_ctx: &Secp256k1, per_commitment_secret: &SecretKey, countersignatory_revocation_base_secret: &SecretKey) -> Result { +pub fn derive_private_revocation_key(secp_ctx: &Secp256k1, + per_commitment_secret: &SecretKey, countersignatory_revocation_base_secret: &SecretKey) +-> SecretKey { let countersignatory_revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &countersignatory_revocation_base_secret); let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret); @@ -311,23 +381,28 @@ pub fn derive_private_revocation_key(secp_ctx: &Secp256k1 Sha256::from_engine(sha).into_inner() }; - let countersignatory_contrib = countersignatory_revocation_base_secret.clone().mul_tweak(&Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap())?; - let broadcaster_contrib = per_commitment_secret.clone().mul_tweak(&Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap())?; + let countersignatory_contrib = countersignatory_revocation_base_secret.clone().mul_tweak(&Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap()) + .expect("Multiplying a secret key by a hash is expected to never fail per secp256k1 docs"); + let broadcaster_contrib = per_commitment_secret.clone().mul_tweak(&Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap()) + .expect("Multiplying a secret key by a hash is expected to never fail per secp256k1 docs"); countersignatory_contrib.add_tweak(&Scalar::from_be_bytes(broadcaster_contrib.secret_bytes()).unwrap()) + .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak commits to the key.") } /// Derives a per-commitment-transaction revocation public key from its constituent parts. This is /// the public equivalend of derive_private_revocation_key - using only public keys to derive a /// public key instead of private keys. /// -/// Only the cheating participant owns a valid witness to propagate a revoked +/// Only the cheating participant owns a valid witness to propagate a revoked /// commitment transaction, thus per_commitment_point always come from cheater /// and revocation_base_point always come from punisher, which is the broadcaster /// of the transaction spending with this key knowledge. /// /// Note that this is infallible iff we trust that at least one of the two input keys are randomly /// generated (ie our own). -pub fn derive_public_revocation_key(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, countersignatory_revocation_base_point: &PublicKey) -> Result { +pub fn derive_public_revocation_key(secp_ctx: &Secp256k1, + per_commitment_point: &PublicKey, countersignatory_revocation_base_point: &PublicKey) +-> PublicKey { let rev_append_commit_hash_key = { let mut sha = Sha256::engine(); sha.input(&countersignatory_revocation_base_point.serialize()); @@ -343,9 +418,12 @@ pub fn derive_public_revocation_key(secp_ctx: &Secp2 Sha256::from_engine(sha).into_inner() }; - let countersignatory_contrib = countersignatory_revocation_base_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap())?; - let broadcaster_contrib = per_commitment_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap())?; + let countersignatory_contrib = countersignatory_revocation_base_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap()) + .expect("Multiplying a valid public key by a hash is expected to never fail per secp256k1 docs"); + let broadcaster_contrib = per_commitment_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap()) + .expect("Multiplying a valid public key by a hash is expected to never fail per secp256k1 docs"); countersignatory_contrib.combine(&broadcaster_contrib) + .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak commits to the key.") } /// The set of public keys which are used in the creation of one commitment transaction. @@ -359,7 +437,7 @@ pub fn derive_public_revocation_key(secp_ctx: &Secp2 /// channel basepoints via the new function, or they were obtained via /// CommitmentTransaction.trust().keys() because we trusted the source of the /// pre-calculated keys. -#[derive(PartialEq, Clone)] +#[derive(PartialEq, Eq, Clone)] pub struct TxCreationKeys { /// The broadcaster's per-commitment public key which was used to derive the other keys. pub per_commitment_point: PublicKey, @@ -384,7 +462,7 @@ impl_writeable_tlv_based!(TxCreationKeys, { }); /// One counterparty's public keys which do not change over the life of a channel. -#[derive(Clone, PartialEq)] +#[derive(Clone, Debug, PartialEq, Eq)] pub struct ChannelPublicKeys { /// The public key which is used to sign all commitment transactions, as it appears in the /// on-chain channel lock-in 2-of-2 multisig output. @@ -418,19 +496,19 @@ impl_writeable_tlv_based!(ChannelPublicKeys, { impl TxCreationKeys { /// Create per-state keys from channel base points and the per-commitment point. /// Key set is asymmetric and can't be used as part of counter-signatory set of transactions. - pub fn derive_new(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, broadcaster_delayed_payment_base: &PublicKey, broadcaster_htlc_base: &PublicKey, countersignatory_revocation_base: &PublicKey, countersignatory_htlc_base: &PublicKey) -> Result { - Ok(TxCreationKeys { + pub fn derive_new(secp_ctx: &Secp256k1, per_commitment_point: &PublicKey, broadcaster_delayed_payment_base: &PublicKey, broadcaster_htlc_base: &PublicKey, countersignatory_revocation_base: &PublicKey, countersignatory_htlc_base: &PublicKey) -> TxCreationKeys { + TxCreationKeys { per_commitment_point: per_commitment_point.clone(), - revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &countersignatory_revocation_base)?, - broadcaster_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_htlc_base)?, - countersignatory_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &countersignatory_htlc_base)?, - broadcaster_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_delayed_payment_base)?, - }) + revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &countersignatory_revocation_base), + broadcaster_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_htlc_base), + countersignatory_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &countersignatory_htlc_base), + broadcaster_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_delayed_payment_base), + } } /// Generate per-state keys from channel static keys. /// Key set is asymmetric and can't be used as part of counter-signatory set of transactions. - pub fn from_channel_static_keys(per_commitment_point: &PublicKey, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1) -> Result { + pub fn from_channel_static_keys(per_commitment_point: &PublicKey, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1) -> TxCreationKeys { TxCreationKeys::derive_new( &secp_ctx, &per_commitment_point, @@ -465,8 +543,8 @@ pub fn get_revokeable_redeemscript(revocation_key: &PublicKey, contest_delay: u1 res } -#[derive(Clone, PartialEq)] /// Information about an HTLC as it appears in a commitment transaction +#[derive(Clone, Debug, PartialEq, Eq)] pub struct HTLCOutputInCommitment { /// Whether the HTLC was "offered" (ie outbound in relation to this commitment transaction). /// Note that this is not the same as whether it is ountbound *from us*. To determine that you @@ -599,9 +677,26 @@ pub fn make_funding_redeemscript(broadcaster: &PublicKey, countersignatory: &Pub /// /// Panics if htlc.transaction_output_index.is_none() (as such HTLCs do not appear in the /// commitment transaction). -pub fn build_htlc_transaction(commitment_txid: &Txid, feerate_per_kw: u32, contest_delay: u16, htlc: &HTLCOutputInCommitment, opt_anchors: bool, broadcaster_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction { +pub fn build_htlc_transaction(commitment_txid: &Txid, feerate_per_kw: u32, contest_delay: u16, htlc: &HTLCOutputInCommitment, opt_anchors: bool, use_non_zero_fee_anchors: bool, broadcaster_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction { let mut txins: Vec = Vec::new(); - txins.push(TxIn { + txins.push(build_htlc_input(commitment_txid, htlc, opt_anchors)); + + let mut txouts: Vec = Vec::new(); + txouts.push(build_htlc_output( + feerate_per_kw, contest_delay, htlc, opt_anchors, use_non_zero_fee_anchors, + broadcaster_delayed_payment_key, revocation_key + )); + + Transaction { + version: 2, + lock_time: PackedLockTime(if htlc.offered { htlc.cltv_expiry } else { 0 }), + input: txins, + output: txouts, + } +} + +pub(crate) fn build_htlc_input(commitment_txid: &Txid, htlc: &HTLCOutputInCommitment, opt_anchors: bool) -> TxIn { + TxIn { previous_output: OutPoint { txid: commitment_txid.clone(), vout: htlc.transaction_output_index.expect("Can't build an HTLC transaction for a dust output"), @@ -609,32 +704,60 @@ pub fn build_htlc_transaction(commitment_txid: &Txid, feerate_per_kw: u32, conte script_sig: Script::new(), sequence: Sequence(if opt_anchors { 1 } else { 0 }), witness: Witness::new(), - }); + } +} +pub(crate) fn build_htlc_output( + feerate_per_kw: u32, contest_delay: u16, htlc: &HTLCOutputInCommitment, opt_anchors: bool, + use_non_zero_fee_anchors: bool, broadcaster_delayed_payment_key: &PublicKey, revocation_key: &PublicKey +) -> TxOut { let weight = if htlc.offered { htlc_timeout_tx_weight(opt_anchors) } else { htlc_success_tx_weight(opt_anchors) }; - let total_fee = feerate_per_kw as u64 * weight / 1000; + let output_value = if opt_anchors && !use_non_zero_fee_anchors { + htlc.amount_msat / 1000 + } else { + let total_fee = feerate_per_kw as u64 * weight / 1000; + htlc.amount_msat / 1000 - total_fee + }; - let mut txouts: Vec = Vec::new(); - txouts.push(TxOut { + TxOut { script_pubkey: get_revokeable_redeemscript(revocation_key, contest_delay, broadcaster_delayed_payment_key).to_v0_p2wsh(), - value: htlc.amount_msat / 1000 - total_fee //TODO: BOLT 3 does not specify if we should add amount_msat before dividing or if we should divide by 1000 before subtracting (as we do here) - }); + value: output_value, + } +} - Transaction { - version: 2, - lock_time: PackedLockTime(if htlc.offered { htlc.cltv_expiry } else { 0 }), - input: txins, - output: txouts, +/// Returns the witness required to satisfy and spend a HTLC input. +pub fn build_htlc_input_witness( + local_sig: &Signature, remote_sig: &Signature, preimage: &Option, + redeem_script: &Script, opt_anchors: bool, +) -> Witness { + let remote_sighash_type = if opt_anchors { + EcdsaSighashType::SinglePlusAnyoneCanPay + } else { + EcdsaSighashType::All + }; + + let mut witness = Witness::new(); + // First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element. + witness.push(vec![]); + witness.push_bitcoin_signature(&remote_sig.serialize_der(), remote_sighash_type); + witness.push_bitcoin_signature(&local_sig.serialize_der(), EcdsaSighashType::All); + if let Some(preimage) = preimage { + witness.push(preimage.0.to_vec()); + } else { + // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay. + witness.push(vec![]); } + witness.push(redeem_script.to_bytes()); + witness } /// Gets the witnessScript for the to_remote output when anchors are enabled. #[inline] -pub(crate) fn get_to_countersignatory_with_anchors_redeemscript(payment_point: &PublicKey) -> Script { +pub fn get_to_countersignatory_with_anchors_redeemscript(payment_point: &PublicKey) -> Script { Builder::new() .push_slice(&payment_point.serialize()[..]) .push_opcode(opcodes::all::OP_CHECKSIGVERIFY) @@ -661,12 +784,30 @@ pub fn get_anchor_redeemscript(funding_pubkey: &PublicKey) -> Script { .into_script() } +#[cfg(anchors)] +/// Locates the output with an anchor script paying to `funding_pubkey` within `commitment_tx`. +pub(crate) fn get_anchor_output<'a>(commitment_tx: &'a Transaction, funding_pubkey: &PublicKey) -> Option<(u32, &'a TxOut)> { + let anchor_script = chan_utils::get_anchor_redeemscript(funding_pubkey).to_v0_p2wsh(); + commitment_tx.output.iter().enumerate() + .find(|(_, txout)| txout.script_pubkey == anchor_script) + .map(|(idx, txout)| (idx as u32, txout)) +} + +/// Returns the witness required to satisfy and spend an anchor input. +pub fn build_anchor_input_witness(funding_key: &PublicKey, funding_sig: &Signature) -> Witness { + let anchor_redeem_script = chan_utils::get_anchor_redeemscript(funding_key); + let mut ret = Witness::new(); + ret.push_bitcoin_signature(&funding_sig.serialize_der(), EcdsaSighashType::All); + ret.push(anchor_redeem_script.as_bytes()); + ret +} + /// Per-channel data used to build transactions in conjunction with the per-commitment data (CommitmentTransaction). /// The fields are organized by holder/counterparty. /// /// Normally, this is converted to the broadcaster/countersignatory-organized DirectedChannelTransactionParameters /// before use, via the as_holder_broadcastable and as_counterparty_broadcastable functions. -#[derive(Clone)] +#[derive(Clone, Debug, PartialEq)] pub struct ChannelTransactionParameters { /// Holder public keys pub holder_pubkeys: ChannelPublicKeys, @@ -680,12 +821,17 @@ pub struct ChannelTransactionParameters { pub counterparty_parameters: Option, /// The late-bound funding outpoint pub funding_outpoint: Option, - /// Are anchors used for this channel. Boolean is serialization backwards-compatible - pub opt_anchors: Option<()> + /// Are anchors (zero fee HTLC transaction variant) used for this channel. Boolean is + /// serialization backwards-compatible. + pub opt_anchors: Option<()>, + /// Are non-zero-fee anchors are enabled (used in conjuction with opt_anchors) + /// It is intended merely for backwards compatibility with signers that need it. + /// There is no support for this feature in LDK channel negotiation. + pub opt_non_zero_fee_anchors: Option<()>, } /// Late-bound per-channel counterparty data used to build transactions. -#[derive(Clone)] +#[derive(Clone, Debug, PartialEq)] pub struct CounterpartyChannelTransactionParameters { /// Counter-party public keys pub pubkeys: ChannelPublicKeys, @@ -736,6 +882,7 @@ impl_writeable_tlv_based!(ChannelTransactionParameters, { (6, counterparty_parameters, option), (8, funding_outpoint, option), (10, opt_anchors, option), + (12, opt_non_zero_fee_anchors, option), }); /// Static channel fields used to build transactions given per-commitment fields, organized by @@ -816,6 +963,7 @@ impl Deref for HolderCommitmentTransaction { fn deref(&self) -> &Self::Target { &self.inner } } +impl Eq for HolderCommitmentTransaction {} impl PartialEq for HolderCommitmentTransaction { // We dont care whether we are signed in equality comparison fn eq(&self, o: &Self) -> bool { @@ -857,7 +1005,8 @@ impl HolderCommitmentTransaction { is_outbound_from_holder: false, counterparty_parameters: Some(CounterpartyChannelTransactionParameters { pubkeys: channel_pubkeys.clone(), selected_contest_delay: 0 }), funding_outpoint: Some(chain::transaction::OutPoint { txid: Txid::all_zeros(), index: 0 }), - opt_anchors: None + opt_anchors: None, + opt_non_zero_fee_anchors: None, }; let mut htlcs_with_aux: Vec<(_, ())> = Vec::new(); let inner = CommitmentTransaction::new_with_auxiliary_htlc_data(0, 0, 0, false, dummy_key.clone(), dummy_key.clone(), keys, 0, &mut htlcs_with_aux, &channel_parameters.as_counterparty_broadcastable()); @@ -884,17 +1033,13 @@ impl HolderCommitmentTransaction { // First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element. let mut tx = self.inner.built.transaction.clone(); tx.input[0].witness.push(Vec::new()); - let mut ser_holder_sig = holder_sig.serialize_der().to_vec(); - ser_holder_sig.push(EcdsaSighashType::All as u8); - let mut ser_cp_sig = self.counterparty_sig.serialize_der().to_vec(); - ser_cp_sig.push(EcdsaSighashType::All as u8); if self.holder_sig_first { - tx.input[0].witness.push(ser_holder_sig); - tx.input[0].witness.push(ser_cp_sig); + tx.input[0].witness.push_bitcoin_signature(&holder_sig.serialize_der(), EcdsaSighashType::All); + tx.input[0].witness.push_bitcoin_signature(&self.counterparty_sig.serialize_der(), EcdsaSighashType::All); } else { - tx.input[0].witness.push(ser_cp_sig); - tx.input[0].witness.push(ser_holder_sig); + tx.input[0].witness.push_bitcoin_signature(&self.counterparty_sig.serialize_der(), EcdsaSighashType::All); + tx.input[0].witness.push_bitcoin_signature(&holder_sig.serialize_der(), EcdsaSighashType::All); } tx.input[0].witness.push(funding_redeemscript.as_bytes().to_vec()); @@ -941,7 +1086,7 @@ impl BuiltCommitmentTransaction { /// /// This class can be used inside a signer implementation to generate a signature given the relevant /// secret key. -#[derive(Clone, Hash, PartialEq)] +#[derive(Clone, Hash, PartialEq, Eq)] pub struct ClosingTransaction { to_holder_value_sat: u64, to_counterparty_value_sat: u64, @@ -1075,12 +1220,15 @@ pub struct CommitmentTransaction { htlcs: Vec, // A boolean that is serialization backwards-compatible opt_anchors: Option<()>, + // Whether non-zero-fee anchors should be used + opt_non_zero_fee_anchors: Option<()>, // A cache of the parties' pubkeys required to construct the transaction, see doc for trust() keys: TxCreationKeys, // For access to the pre-built transaction, see doc for trust() built: BuiltCommitmentTransaction, } +impl Eq for CommitmentTransaction {} impl PartialEq for CommitmentTransaction { fn eq(&self, o: &Self) -> bool { let eq = self.commitment_number == o.commitment_number && @@ -1107,6 +1255,7 @@ impl_writeable_tlv_based!(CommitmentTransaction, { (10, built, required), (12, htlcs, vec_type), (14, opt_anchors, option), + (16, opt_non_zero_fee_anchors, option), }); impl CommitmentTransaction { @@ -1139,9 +1288,18 @@ impl CommitmentTransaction { transaction, txid }, + opt_non_zero_fee_anchors: None, } } + /// Use non-zero fee anchors + /// + /// (C-not exported) due to move, and also not likely to be useful for binding users + pub fn with_non_zero_fee_anchors(mut self) -> Self { + self.opt_non_zero_fee_anchors = Some(()); + self + } + fn internal_rebuild_transaction(&self, keys: &TxCreationKeys, channel_parameters: &DirectedChannelTransactionParameters, broadcaster_funding_key: &PublicKey, countersignatory_funding_key: &PublicKey) -> Result { let (obscured_commitment_transaction_number, txins) = Self::internal_build_inputs(self.commitment_number, channel_parameters); @@ -1180,7 +1338,7 @@ impl CommitmentTransaction { let script = if opt_anchors { get_to_countersignatory_with_anchors_redeemscript(&countersignatory_pubkeys.payment_point).to_v0_p2wsh() } else { - get_p2wpkh_redeemscript(&countersignatory_pubkeys.payment_point) + Payload::p2wpkh(&BitcoinPublicKey::new(countersignatory_pubkeys.payment_point)).unwrap().script_pubkey() }; txouts.push(( TxOut { @@ -1342,7 +1500,7 @@ impl CommitmentTransaction { pub fn verify(&self, channel_parameters: &DirectedChannelTransactionParameters, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1) -> Result { // This is the only field of the key cache that we trust let per_commitment_point = self.keys.per_commitment_point; - let keys = TxCreationKeys::from_channel_static_keys(&per_commitment_point, broadcaster_keys, countersignatory_keys, secp_ctx).unwrap(); + let keys = TxCreationKeys::from_channel_static_keys(&per_commitment_point, broadcaster_keys, countersignatory_keys, secp_ctx); if keys != self.keys { return Err(()); } @@ -1402,11 +1560,11 @@ impl<'a> TrustedCommitmentTransaction<'a> { let keys = &inner.keys; let txid = inner.built.txid; let mut ret = Vec::with_capacity(inner.htlcs.len()); - let holder_htlc_key = derive_private_key(secp_ctx, &inner.keys.per_commitment_point, htlc_base_key).map_err(|_| ())?; + let holder_htlc_key = derive_private_key(secp_ctx, &inner.keys.per_commitment_point, htlc_base_key); for this_htlc in inner.htlcs.iter() { assert!(this_htlc.transaction_output_index.is_some()); - let htlc_tx = build_htlc_transaction(&txid, inner.feerate_per_kw, channel_parameters.contest_delay(), &this_htlc, self.opt_anchors(), &keys.broadcaster_delayed_payment_key, &keys.revocation_key); + let htlc_tx = build_htlc_transaction(&txid, inner.feerate_per_kw, channel_parameters.contest_delay(), &this_htlc, self.opt_anchors(), self.opt_non_zero_fee_anchors.is_some(), &keys.broadcaster_delayed_payment_key, &keys.revocation_key); let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc, self.opt_anchors(), &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key); @@ -1428,30 +1586,13 @@ impl<'a> TrustedCommitmentTransaction<'a> { // Further, we should never be provided the preimage for an HTLC-Timeout transaction. if this_htlc.offered && preimage.is_some() { unreachable!(); } - let mut htlc_tx = build_htlc_transaction(&txid, inner.feerate_per_kw, channel_parameters.contest_delay(), &this_htlc, self.opt_anchors(), &keys.broadcaster_delayed_payment_key, &keys.revocation_key); + let mut htlc_tx = build_htlc_transaction(&txid, inner.feerate_per_kw, channel_parameters.contest_delay(), &this_htlc, self.opt_anchors(), self.opt_non_zero_fee_anchors.is_some(), &keys.broadcaster_delayed_payment_key, &keys.revocation_key); let htlc_redeemscript = get_htlc_redeemscript_with_explicit_keys(&this_htlc, self.opt_anchors(), &keys.broadcaster_htlc_key, &keys.countersignatory_htlc_key, &keys.revocation_key); - let sighashtype = if self.opt_anchors() { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All }; - - // First push the multisig dummy, note that due to BIP147 (NULLDUMMY) it must be a zero-length element. - htlc_tx.input[0].witness.push(Vec::new()); - - let mut cp_sig_ser = counterparty_signature.serialize_der().to_vec(); - cp_sig_ser.push(sighashtype as u8); - htlc_tx.input[0].witness.push(cp_sig_ser); - let mut holder_sig_ser = signature.serialize_der().to_vec(); - holder_sig_ser.push(EcdsaSighashType::All as u8); - htlc_tx.input[0].witness.push(holder_sig_ser); - - if this_htlc.offered { - // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay. - htlc_tx.input[0].witness.push(Vec::new()); - } else { - htlc_tx.input[0].witness.push(preimage.unwrap().0.to_vec()); - } - - htlc_tx.input[0].witness.push(htlc_redeemscript.as_bytes().to_vec()); + htlc_tx.input[0].witness = chan_utils::build_htlc_input_witness( + signature, counterparty_signature, preimage, &htlc_redeemscript, self.opt_anchors(), + ); htlc_tx } } @@ -1486,25 +1627,21 @@ pub fn get_commitment_transaction_number_obscure_factor( | ((res[31] as u64) << 0 * 8) } -fn get_p2wpkh_redeemscript(key: &PublicKey) -> Script { - Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0) - .push_slice(&WPubkeyHash::hash(&key.serialize())[..]) - .into_script() -} - #[cfg(test)] mod tests { use super::CounterpartyCommitmentSecrets; - use ::{hex, chain}; - use prelude::*; - use ln::chan_utils::{get_htlc_redeemscript, get_to_countersignatory_with_anchors_redeemscript, get_p2wpkh_redeemscript, CommitmentTransaction, TxCreationKeys, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, HTLCOutputInCommitment}; + use crate::{hex, chain}; + use crate::prelude::*; + use crate::ln::chan_utils::{get_htlc_redeemscript, get_to_countersignatory_with_anchors_redeemscript, CommitmentTransaction, TxCreationKeys, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, HTLCOutputInCommitment}; use bitcoin::secp256k1::{PublicKey, SecretKey, Secp256k1}; - use util::test_utils; - use chain::keysinterface::{KeysInterface, BaseSign}; + use crate::util::test_utils; + use crate::chain::keysinterface::{KeysInterface, BaseSign}; use bitcoin::{Network, Txid}; use bitcoin::hashes::Hash; - use ln::PaymentHash; + use crate::ln::PaymentHash; use bitcoin::hashes::hex::ToHex; + use bitcoin::util::address::Payload; + use bitcoin::PublicKey as BitcoinPublicKey; #[test] fn test_anchors() { @@ -1513,22 +1650,23 @@ mod tests { let seed = [42; 32]; let network = Network::Testnet; let keys_provider = test_utils::TestKeysInterface::new(&seed, network); - let signer = keys_provider.get_channel_signer(false, 3000); - let counterparty_signer = keys_provider.get_channel_signer(false, 3000); + let signer = keys_provider.derive_channel_signer(3000, keys_provider.generate_channel_keys_id(false, 1_000_000, 0)); + let counterparty_signer = keys_provider.derive_channel_signer(3000, keys_provider.generate_channel_keys_id(true, 1_000_000, 1)); let delayed_payment_base = &signer.pubkeys().delayed_payment_basepoint; let per_commitment_secret = SecretKey::from_slice(&hex::decode("1f1e1d1c1b1a191817161514131211100f0e0d0c0b0a09080706050403020100").unwrap()[..]).unwrap(); let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret); let htlc_basepoint = &signer.pubkeys().htlc_basepoint; let holder_pubkeys = signer.pubkeys(); let counterparty_pubkeys = counterparty_signer.pubkeys(); - let keys = TxCreationKeys::derive_new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint).unwrap(); + let keys = TxCreationKeys::derive_new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint); let mut channel_parameters = ChannelTransactionParameters { holder_pubkeys: holder_pubkeys.clone(), holder_selected_contest_delay: 0, is_outbound_from_holder: false, counterparty_parameters: Some(CounterpartyChannelTransactionParameters { pubkeys: counterparty_pubkeys.clone(), selected_contest_delay: 0 }), funding_outpoint: Some(chain::transaction::OutPoint { txid: Txid::all_zeros(), index: 0 }), - opt_anchors: None + opt_anchors: None, + opt_non_zero_fee_anchors: None, }; let mut htlcs_with_aux: Vec<(_, ())> = Vec::new(); @@ -1543,7 +1681,7 @@ mod tests { &mut htlcs_with_aux, &channel_parameters.as_holder_broadcastable() ); assert_eq!(tx.built.transaction.output.len(), 2); - assert_eq!(tx.built.transaction.output[1].script_pubkey, get_p2wpkh_redeemscript(&counterparty_pubkeys.payment_point)); + assert_eq!(tx.built.transaction.output[1].script_pubkey, Payload::p2wpkh(&BitcoinPublicKey::new(counterparty_pubkeys.payment_point)).unwrap().script_pubkey()); // Generate broadcaster and counterparty outputs as well as two anchors let tx = CommitmentTransaction::new_with_auxiliary_htlc_data( @@ -1609,9 +1747,9 @@ mod tests { assert_eq!(tx.built.transaction.output[0].script_pubkey, get_htlc_redeemscript(&received_htlc, false, &keys).to_v0_p2wsh()); assert_eq!(tx.built.transaction.output[1].script_pubkey, get_htlc_redeemscript(&offered_htlc, false, &keys).to_v0_p2wsh()); assert_eq!(get_htlc_redeemscript(&received_htlc, false, &keys).to_v0_p2wsh().to_hex(), - "002085cf52e41ba7c099a39df504e7b61f6de122971ceb53b06731876eaeb85e8dc5"); + "0020e43a7c068553003fe68fcae424fb7b28ec5ce48cd8b6744b3945631389bad2fb"); assert_eq!(get_htlc_redeemscript(&offered_htlc, false, &keys).to_v0_p2wsh().to_hex(), - "002049f0736bb335c61a04d2623a24df878a7592a3c51fa7258d41b2c85318265e73"); + "0020215d61bba56b19e9eadb6107f5a85d7f99c40f65992443f69229c290165bc00d"); // Generate broadcaster output and received and offered HTLC outputs, with anchors channel_parameters.opt_anchors = Some(()); @@ -1628,9 +1766,9 @@ mod tests { assert_eq!(tx.built.transaction.output[2].script_pubkey, get_htlc_redeemscript(&received_htlc, true, &keys).to_v0_p2wsh()); assert_eq!(tx.built.transaction.output[3].script_pubkey, get_htlc_redeemscript(&offered_htlc, true, &keys).to_v0_p2wsh()); assert_eq!(get_htlc_redeemscript(&received_htlc, true, &keys).to_v0_p2wsh().to_hex(), - "002067114123af3f95405bae4fd930fc95de03e3c86baaee8b2dd29b43dd26cf613c"); + "0020b70d0649c72b38756885c7a30908d912a7898dd5d79457a7280b8e9a20f3f2bc"); assert_eq!(get_htlc_redeemscript(&offered_htlc, true, &keys).to_v0_p2wsh().to_hex(), - "0020a06e3b0d4fcf704f2b9c41e16a70099e39989466c3142b8573a1154542f28f57"); + "002087a3faeb1950a469c0e2db4a79b093a41b9526e5a6fc6ef5cb949bde3be379c7"); } #[test]